Spray producing device



Sept- 13, 1932- P. s. cAsE SPRAY PRDUVCING DEVICE 3 Sheets-Sheet l Filed Feb. 8. 1929 xNvENToR,

. y BY .f' l ATTORNEYS.

F116!! Fb. 8, 1929 3 Sheets-Sheet 2 INVENTOR l ATTORNEYS.

Sept. 13, 1932. P, 5 CASE 1,876,611

SPRAY PnoDUc'ING DEvIE Filed Feb. 8; 1929 3 Sheets-Sheet 3 INVENTOR n l l ATTORNEYS.

aoy

, solid material Patented Sept. 13, 1932 UNITED STATES PATENT o1-FICE PHILIP S. CASE, OF NIAGARA FALLS, NEW YORK, A-SSIGNOR ELECTRO METALLURGI- CAL COMPANY, A XCORPORATION OF WEST VIRGINIA SPRAY PRODUCING DEVICE Application filed. February 8, 1929. lSerial No. 338,587.

My invention relates to spraying devices and especially vto such devices wherein air under pressure is used to project subdivided at a comparatively low velocity and to control the mixing of liquids with the solids so as to produce coatings of liquid impregnated solids.

lt is among the objects of -rny invention to separately project aniixture of air and powdered solid, amixture of air and liquid 1 binder and a current of air from the device and to form a moistened composition outside of the'device. i

Another object of my invention is to project the moistened solids against the object to be coated at such ra low velocity that fragile parts of the object may be coated Without being injuriously adected 'by' the force of the projected material.

Another object of my invention is to produce a thorough moistening of the powder exterior of the device and atthe same time to control the character of the coating produced as well as increase and decrease the rate of deposition..

My invention may be embodied in devices whichare used to/produce coatings of metal powders on sand casting molds. Thel ac-I companying drawings illustrate such a device in which Fig. 1 ils a diagrammatic view of the air, powders-and binder supply system,

Fig.'2"i'sy a longitudinal sectional view of a spray gun, y.

Fig. 3 is an enlarged longitudinal sectional view of the nozzle of the spray gun shown in Fig. 2,

Fig. 4 is a view in side elevation of the air distributing ring,

Fig. 5 is a view partially in cross-section of the air distributing ring taken along the line V-V of'Fig. 4,

Fig. 6 is a view in side elevation of the emulsifier ring,

Fig. 7 is a view partially in cross-section of the emulsifierring taken along the line VII-VII of Fig. 6, i

Fig. 8 is a view in slde -elevation of the nipple member,

Fig. 9 is an end elevational view of the nipple member shown in Fig. 8,

Fig. 10 is a sectional view of the nipple menber taken along theline X-X of Fig. 9, an

Fig. 11 is a cross sectional view of the air and powder mixer.

The device consists broadly of means to mix powdered solids and air, means to emulsify liquid binder and air, means to equalize the pressure of air and the air and binder mixture, and means to combine the said mixtures and to produce a low nozzle velocity of the mixtures which are mingled at points external of the nozzle.

y The air is supplied through a main high pressure conduit 1, as shown in Figure 1, which is Vconnected to a `source of air under pressure such as the compressed air tank 2. The pressure of the air in tank 2 may be reduced to the maximum working pressure through a reducing valve 3. The air is supplied from the main line 1 through branch pipes`4 and 5 to the powdered metal and liquid containers respectively and to the head of the spray gun through a pipe 6 which may be provided with an air regulating valve 7 mounted either on the spray gun assem or near the branch pipes 4 and 5..

The branch pipe 4 leads to the powder reservoir 10 through a pressure reducing bly valve 11. A branch 12 in pipe 4 conducts air around the reservoir through a nozzle (b) in the dust mixer 13 so that the same relative fluctuations in the air pressure are communicated 'to the powdered metal in the chamber of the r servoir 10 and to the dust mixer 13.

The ietal powder flows through the con? nection 15 around the end of nozzle (b) as shown in Fig. 11 where it is picked up bythe air, atomized and carried forward into the pipe 16 whichis attached to the mixer by appropriate connections'. The nozzle or orice tube (b) is carried by an adjusting nipple (d) The adjusting nipple (d) is provided with a slot (e) in which a screw driver can be inserted to screw the nipple back and` forth to vary the supply'of metal powder.

In order to produce a uniform continuous supply of mixed powder and air at a lov tions in air supplv a J' velocity, it has been found necessa to have an air pressure on the solids in ta 10 sucient to force them around and in front of the nozzle (b) and to employ the air discharged from the nozzle merely as a mixing, atomizing, and propelling a entafter the solids are delivered to the env of the nozzle. To obtain this action means are provided in the by-pass 12 to restrict the byass so that a lower pressure .of air will be elivered to the mixer 13 than to the tank 10. 14 in by-pass 12 is a convenient means of producing the restriction and the valve has the further advantage of being adjustable' so that various qonditions of air supply for the jet may be arranged, but other means to restrit and regulate the by-pass 12 may be use Within certain limits the diderences in iinenessor density of the powder and variapressure may be compensated for by usting the valve 14, but all sizes of powder cannot be atomized with the best results into a low velocit stream with a given nozzle adjustment. ith finer Apowders the nozzle usually operates best when the tip is positioned well beyond the entrance of branch 5 but the nozzle may be adjusted back for coarser powders by turning the nipple (d).

Longer jets and smaller openings around the nozzle may be used with free owing powders while a larger or smaller jet may be used to increase or decrease the volume of air and the initial jet velocity. Good atomization at low velocity has been obtained with ferro-chrome powderL which was ground to pass a screen of 30 meshes to the inch and retained on a screen of60 meshes to the inch with the following nozzle and adjustments: a one eighth inch diameter jet (b), and an annular spacing of one quarter inch between the walls of the nozzle and mixer with the nozzle projected entirely across a one half inch diameter solids-pipe 5. With a more dense powder, ferro-tungsten of thesame ineness, a shorter jet gave about the same results. Free flowing powders and lower density solids generally require a smaller pressure in the tank 10 so as toropel them around the nozzle while more ensesolids require more violent atomizing conditions at the jet. ll make the proper variations by means of theyvalve 14 in by-pass 12, by, interchanging larger and smaller jets and by varying the projection of the nozzle, across the branch 5.

Ari air relief valve 17 in the top of the tank 10 is used to start and stop the flow of metal powder to the dust mixer 13. To start the dust mixer the valves 11 and 14 are opened. Valve 17 is then closed and the ldust is forced down through the pipe 15 picked-up by the air issuingfrom nozzle (b) and carried in a cloud into the pipe 16. 'llheamount The valvey Lemert of air admitted Vto the mixer 13 and the velocity of the mixture delivered by the mixer is regulated by opening the valve 14 more or less. The mixer is stopped merely by opening the valve 17'. IThis relieves the pressure of the air in the tank 10 and stops'the How of dry powder. The ilow of air through 4the by-pass 12 and mixer 13 is usually continued at least until all the owder is discharged from the pipe 16. n order at all times to have a small amount of air passing through the by-pass 12 and pipe 16, l may put an auxiliary by-pass around valve 11 and regulate the valve 18 therein so that a small leakage of air will always exist from the main supply through the conduit 16.

The branch pipe 5 leads to the top of a container 20 which holds a supply of liquid binder. A by-pass 21 from the branch pipe 5 conducts air to the liquid mixer at a pressure and with the same pressure fluctuations as those prevailing in the tank 20. A pressure reducinggvalve 22 is connected in the pipe 21 to roughly regulate the supply of air to the liquid mixer 23. Liquid/is supplied to the mixer frkbm the bottom of tank 20 through the valve 24 and pipe 25. rlhe liquid mixer 23 may be connected under or near the tank 20 as shown in broken ,lines in Figure 1, but

'in the spray gun and consists of an extension .26 of the liquid pipe 25 which is arranged to discharge into an extension ofthe air pipe 21 at an angle of about 30. A brace 30 `is provided between pipes 21 and 26 to strengthen the device. Valves 32 and 31 in the air and 'liquid pipes regulate the supply of air and bider respectively. The mixer 23 is apreliminary mixer for the binder, its function being'to produce a .regulated supply of air mixed with a constant regulated supply of liquid binder and to project the mixture into the passage 33 which is connected through the handle of the gun to a passage 51 in the gun head.' j

The spray gun shown in Figures 2 and 3 consists further of a handle portion which may be formed around an enlarged central pipe 35 carrying a bracket 36.- The bracket 36 is provided with openings through which the binder mixture pipe 33 and the air pipe 6 are passed. Pipes 6 and 33may be fitted on one end with unions 6 and 33 so that they may be readily discbnnected. 'llhe forward ends of these pipes are connected to a support 34 through nipples 37 and 38, and the spray gun head 39 is secured to the plate 34 by a plurality of screws 40. The central pipe reducer 42 to which the dust mixture pipe 16 is attached.

A mixture of air and metal dust is extremely abrasive and will grind away a metal conduit at a rapid rate. I have found that this mixture can be successfully'transpbrted inl pipes which have a lining lof resilient plastic material. For the best results I use a gum rubber hose 43 as a lining for the pipe 35. The rubber hose 43 is extended through the central opening in the gun head and terminates in the exit nozzle 52. The hose 43 is passed through the gun head and pipe 3'5 and the inner end of the hose is forced over a short frusto-conically shaped ferrule 44 which expands the end of the hose. The extended end of the hose bears against the end of thepipe and against' the reducer 42 which holds it in place when the reducer is screwed down.

of the headis cut away, so as to form' sections v severally cutting across passages and 51. Reduced cylindrical sections and shoulders are formed in this operation so thatl suitable fitting pieces and collars may be attached and chambers formed for mounting the various parts of the equalizer for the air and the emulsifier for the airand binder mixture.

The air passage 50 opens into a circular chamber 60 Figure 3 which is formed by cutting a circular groove in the shoulder 61. The larger reduced barrel portion of the head is threaded and 'a flat perforated ring 62 is screwed on the reduced portion to form the forward wall of the air chamber 60. The flat ring 62 may have small equally spaced perforations 63 around its entire circumference but I prefer" to leave unperforated a segment 64 which may subtend an angle of yabout 30at the center 'of the ring. The

opposite the passage 50 and' serves a a balie unperforated portionof the ring E spaced.A

upon which the air impinges and t around the chamber and equalizes to some i extent through the perforations'b. Anipple member 65 having a beveled portion 6 6 is screwed on this reduced portion and forms another annular chamber 71. '(The nipple 65 is reduced at its forward end to a section 67 which extends Ibeyond the barrel portion 88 of the gun head. The nipple 65 is locked by a cap 70 which is threaded on the gun asses tween the ring 62, the beveled edge 66 of the 70 nipple 65 and a wall of the cap 70. v The air is again and more completely equalized by passing it around the ynipple member 65 next to the inner wall of the cap 7 0. The l passage between the cap and the nipple mem- Jber may be a narrow circular space or grooves@ 75 may be cut across the Jface of the nipple member 65. The lgrooves 75 are preferably spirally disposed and direct the air tangentially into an annular chamber 76 which is formed betwen the reducedl end 67 of the nipple 65 .and the end wall of the cap 70. The chamber 76 is preferably of sufficient depth to give a considerable free space in Y which the air from the grooves 75 may be. 85 swirled and caused to` cut across the small openings 7 8vwhich are spaced around the cir. cumference of the reduced part 67 and direct the air so as to agitate the stream of -air and metal powder issuing from the passage 52. a The direction of the air issuing from the openings 78 may be made to change the character of the spray accordingly as the air is directed perpendicularly, or obliquely, to the axis of the powder mixture. Obliquity of the air jets maybe obtained by advancing the fitting piece 67 v`so that the jet-s 78 willvbe ob structed more or less by the end lof the barrel.

The orifices 78 may be directed tangentially toward the current of metal 'and air which issues from the exit 52 in `Qrder to give a swirling motion or they may be directed raf dially atan angle to the axis of the passage 53. I prefer to vspace the small oriices 78 equally andto direct them radially and-iperpendicularly to the axis of theu passage'v 53. The pressure'of the air which is discharged throughl the orifices 78 is'equalized and the jets constitute a screen of air through which the liquid binder and metal powder mixture y,

pass and they are subjected to violent agitation.

The mixture of air and liquid binder which is formed in the mixer 23 is conducted through the passage 51 and discharged into an annular chamber 85 of the emulsilier. y The chamber 85.i`s lformed between the shoulder 86 of the 'head 39and a collar 87 which is Agiven a sliding itcn the reduced portion 88 4of the head.

The collar y87 is grooved on its liat faces.r These grooves 89 and 89 as shown inv Figures 6 and 7 may be inclined to the radii ofv the collar or they maybe cut radially on'the A face oit the collar. I prefer to cut the grooves radially in a staggered relation to each other in tle opposite faces of lthe collar as shown in Figure 6. This arrangement helps to dis'- perse the air throughout the liquidand to throughthe grooves 89 across the edge of the collar in a spiral direction and then through the grooves 89. 'Ihe collar 87 is slightly smaller than the threaded bore of the fitting piece and an annular passage between the fitting piece having a corrugated wall is [formed by the threaded bore. The threads also serve to disperse the air in the liquid during its passage across the face of the collar 87.

The face 90 of the nipple member 65 forms the outer wall of a passage which conducts the emulsion to the exit orifices 91 which are.

spaced around the reduced part 88. The orifices 91 are formed by boring the iitting piece 65 so as to slidably fit over the part 88 and then grooves 91 are cut in the inner face of the fitting piece.v 'lhese-v grooves preferably traverse the inner face of the fitting piece 65 parallel to the axis of the gun head but they may be cut along other lines, as for example, spirals. I prefer to make the exterior of the barrel 88 and the interior of the nipple cylindrical and to cut a large number of grooves 91 in the part 67 and to provide means so as to give thejets of emulsion an impulse which will converge the jets. A

groove 93 having an arcuate cross-section is cut around the barrel 88 for this purpose. The nipple member 65 with its grooves 91 extends beyond the-tip of the barrel 88 and the orifices 78 -or theair, are located beyond the end of the barrel so that the envelope of v regulated quantity romfthe tank 20 through passage 2 5to the mixer 23 and`mixed with the desired quantity of air which is suppliedV through passage 21. The discharge from the mixer 23 isa stream of binder interspersed with air. This is broken up, homogenized or emulsified and equalized in the emulsiiier in the head of the spray gun and the emulsion is discharged Vthrough the passages 91 in a plurality of ine jets which form a cylindrical envelope around the air and powder discharge.,v They air is conducted through passages and 50, and the air equalizer in the gun head, 'and is discharged through the ports 7 8 so as to violently agitate the air and powder mixture after it issues from the nozzle. The violently agitated mixture of ythe airand powder mixture almost instantly fpicks vup thee'nvelope of liquid binder and l yabsorbs the liquid, so .that at a short distance` l from' the nozzle, acomposite jet of uniformly moistened powder suspended vin air is formed.' The-'velocity ofthe stream of moistended powder, its wetness and its dilution with air may be regulated by admitting more or less air and liquid binder to the system. For coating sand molds, the stream of moistened powder is projected against the surface of the mold where it forms a more or less porous coating depending on the wetness of the powder, the degree of compactness of the powder, and the size of the solid particles.

It is evident that various modifications oi thc device described may be made without departing from the spirit of my invention.

Therefore, I do not wish to be understood as limiting my invention except b the prior art and by the invention as de edL in the claims annexed hereto.

I claim as my invention:

1. In a device for producing a spray of gas, liquid and solids, a source of gas under pressure, a container for comminuted solids, a container for liquid, mixersfor solid and gas and for liquid and gas, a conduit for the solid and .gas mixture having a discharge orilice, a conduit adapted to discharge the mixture of liquid and gases in an envelope around the discharged solid and gas mixture and a conduit for gas having orifices to project the gas into the discharged mixture of solid and gas, a communication for conducting ga's from said source to said solids container, a by-pass around said' solids container connecting said communication and the solidsrmixer and a valve in the solids container to relieve the air pressure therein and stop Ithe flow of solids.

2. A device for producing a spray 'of gas, liquid and solids which comprises a source of gas under pressure, means to mix gas and solids, means to mix liquid and gas, passage means to'conduct gas and said mixtures to discharge orifices, the means for conducting and discharging the liquid and gasmixture head having a reduced portion, a nipple member attached to said head having a recessed portion adapted to form a chamber around said body communicating with one of said bores, a ring member in said chamber for forming a tortuous passage therein, said reduced portion and nipple forming a discharge passage which communicates with the chamber.

3. A device for producing a spray of gas 'including a head portion having bores, said i and ,-liquid-moistened solids which comprises a a source of, gas under pressure, means to mix gas and solids, means to mix liquid and gas, passage means to conduct gas and said mixtures to discharge orifices, the means for conducting and discharging the liquid and gas l mixture including a head having bores, said head having a reduced portion, a nipple member attached to'said head having a recessed portion adapted to forma chamber around said body communicating with one'of said vio Y tures to discharge oriices,

bores, a ring member in said chamber for forming a tortuous passage therein, said ring having grooves on its ilat faces, said body and nipple lforming a discharge passage which communicates withl the chamber.

4. A device for producing a spray of gas and liquid-moistened solids which comprises a source of gas under pressure, means to mix gas and solids, means to mix liquid and gas, passage means to conduct gas and said mixthe means for conducting the liquid and gas mixture including `a head having bores, a reduced portion in said head, a nipple member attached to said head having a recessed portion adapted to form a chamber around said body communieating with one of said bores, an obstruction in said chamber forming a tortuous passage l therein, said nipple having an inner bore with grooves which communicate with said chamber and form discharge passages between the nipple and the reduced portion of the'body.

5. A device for producing a spray of gas and liquid-moistened solids which comprises a source oi gas under pressure, means to mix gas and solids, means to mix liquid and gas, passage means to conduct gas and saidmixtures to duct gas cap for said head, a head, a recessed nipple member on said reincluding a head having bores, a

v cap for said head, a reduced portion on said head, a recessed nipple member on said head forming with` said cap an intermediate chamber communicating with one of said bores and a discharge chamber, said nipple having groovesin its outer surface to provide passages between the chambers and ports to conduct air from the discharge chamber.

7. A device for producing a spray of gas and liquid-moistened solids which comprises a source of gas under pressure, means to mix gas and solids, means passage means to conduct gas and'said mixture's" to discharge orifices, the means to' conduct gas including 'ajhead having bores, a cap for said head, a reducedv portion on said head, a recessed 'nipple member on said head forming with said cap an intermedi-ate chamber communicating with one of said boies and a discharge chamdischarge orifices, the means to conreduced portion on said` orifices, the means to conto mix liquid and gas,

ber, sala nipple having spiral grooves in its' outer surface to provide passages between the chambersL and ports to project air from the discharge chamber transversely of the discharged mixture of solids and air.

8. A device for producing a spray of gas and liquid-meistened solids which comprises a source of gas underupressure, means to mix gas and solids, means to mix liquid and gas, passage means to 'conduct gas and said mixtures to discharge oriices, the means to con-v .head having bores, a -cap for said head, a reduced portion of said head, a recessed nipple member on said head duct gas including a forming with said cap an intermediate chamber communicating with one of said bores and a discharge chamber,y said nipple having grooves .in one portion communication between the chambers and to produce agitation of air in the discharge chamber and ports to project air from the discharge chamber in a direction perpendicular to the axis of the bore for the solids and gas mixture.

9. A device for producing a spray of solids, liquid and gas which comprises a spray gun adapted lio combine constituents of said spray, a mixer forsolids and gas, a reservoir lfor subdivided sdlids, a conduit for supplying gas to the reservoir at a predetermined pressure to expel solids therefrom and a pipe to conduct solids 'to the mixer; a by-pass connecting said conduit and mixer, and adjustable means to regulate the gas in the by-pass so as to supply gas to the mixer at a lower pressure than said predetermined pressure.

10. A device for producing a spray of solids, liquid and gas which comprises a spray gun adapted to combine constituents of said spray, a mixer a reservoir for subdivided solids, aconduit connecting'said reservoir with a source of' pressure-gas, so as to expel solids from the reservoir' with a pressure reducing valve in said conduit to supply gas to the reservoir vat a predetermined pressure, 'ing belovvr said said mixer bereservoir so as to receive the expelled solids, ahy-pass leading to said mixer and connected between said reducing valve and reservoir, means in said by-pass to supply thereof to provide ics for solids and gas,

no s

gas to the mixer at a lower pressure than said y predetermined pressure, a by-pass around said reducing valve to provide a leak between the `pressure source and the mixer, and

means to conduct the mixture of solids and gas to the spray gun head.

11. A device :for producing a spray of solids, liquid and gas which comprises a spray gun adapted to combine constituents of said for olids and gas, a reservoir spray, a mixer for subdivided solids, means to supply gas pressure to said reservoir, means to supply gas to said mixer at a. lower pressure than 'the gas in the reservoir, a liquid reservoir connected to asource of gas under pressure, a mixer for liquid and gas connected to said gas-source and to said liquid reservoir, a pres-4 sure reducing valve between the liquid mixer and the source of gas and means to conduct mixed solids and gas and mixed liquid and gas to the spray gun head. V

12. A device for producing a spray of solids, liquid and' gas which comprises a spray gun adapted to combine'constituents of said spray, a mixer for solids and gas, a reservoir for subdivided solids, means to supply gas pressure to said reservoir, means to supply gas to said mixer at a lower pressure than the gas in the reservoir, a liquid reservoir connected to a source of gas under pressure, a mixer for liquid and gas connected to said gas-source, and to said liquid reservoir, means to regulate the flow of liquid supplied to said liquid mixer, a pressure reducing valve between the liquid mixer and the source of gas, and means to conduct mixed solids and gas and mixed liquid and gas to the spray gun head. l

13. A device for producing a spray of solids, liquid and gas which comprises a spray gun head adapted to combine the constituents of said spray, a source ofpressure gas, a main gas connection between said sourceand the spray gun head, a liquid and gas mixer having' a connection with lsaid spray gun head arid including a liquid reser-J voir adapted to be subjectedto a high pressure of gas, means to mix liquid under pressure with gas at a pressure lower than that obtaining in said mainA gas connection. or

reservoir, a solid and gas mixer having a conf nection with the spray gun head, a reservoir for solids adapted to be subjected to a lower pressure thansaid liquid reservoir or said main gaslconnection, a connection between the mixer and solids reservoir, a connection on the solids mixer with a gas pressure supply which gives a lower pressure than that obtained in said solids reservoir and a nozzleA in said solids mixer adapted to commingle the solidsfand gas whereby a low velocity cur rent of" mixed powder and gas maybe deliverecl.`

pressed upon the 'reservoir whereby alow velocity current of mixed solids and gas is d elivered to the spray gun head, a mixer for llquid and gas having a gas connection with 'the source of gas, means to deliver liquid from said reservoir'to the liquid mixer at a higher pressure than the gas delivered thereto, whereby a mixture of liquid and gas is delivered to the spray gun head, a gas conaarden nection between the source of gas and the spray gun head capable of delivering gas at a pressure higher than the gas delivered to either of said mixers, means in said spray gun to discharge the mixture of liquid vand gas as an envelope around a central spray of solids and gas and vmeans to inject the gas into'the central sprayof solids and gas at an angle to the axis thereof.

r 15. The combination with means to1pr0- 'Z5 Vide a low velocity current of mixed solids and gas, means to provide a current of mixed liquid and gas and means to provide a current of gas, of a device to project said cur- !l'ents and combine the same external of said device which comprises a spray gun head having longitudinally arranged passages to conduct, said gas and said mixture separately through the head, means in the air conducting passage to equally distribute the ai'r annularly around said head, a fitting piece on said head having air discharge ports directed at an angle to the axis of the head and communicating with the air passage.4 c "1 16. A device for producing a spray of solids which comprises a reservoir for sub.- divided solids, a mixer having a, chamber communicating with the solids reservoir, a connection adapted to supply gas under pressure to the contents of said reservoir, a gas connection on themixer havingmeans adapted to supply-gas thereto at a lower pressure than that supplied to the contents of the reservoir, said gas connection including` a removable nozzle which extends into -said chamber, 10o means to mount the nozzle so as to immerse it with solids under pressure and to adjust the extension of the nozzle into said chamber, and means to conduct mixed solids and gas from the chamber.

'17. A device for producing a 4spray of solids which comprises a reservoir for subdivided solids, a tubular mixer havin a ,chamber and side connection communicating l with the solids reservoir, a connection adapt- 11o led to supply gas under pressure tothe contents of' the reservoir, a as connection on the mixer adapted to supp y gas thereto at a lower` pressure than that supplied to the oontents of the reservoir, said gas connection 11.: on themixer having an axially disposed nozzle 'which is. adapted to be immersed with solids under pressure and means communicating w1 said chamber to conduct mixed solids and gas from the mixer.

. )In` testimony whereof I'aiix my si y rinmr s.

y ature. ASE. 

